A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6650-00-578-6543
NSN 6645-01-320-4138
NSN 5960-00-329-9281
NSN 5945-01-461-8143
NSN 6610-01-246-5881
NSN 6685-01-289-4808
NSN 6150-00-369-0376
NSN 5935-00-256-3535
NSN 5990-00-212-4316
NSN 5996-00-283-3710
NSN 2925-00-922-3785
NSN 6685-00-342-9408